Lecture 3: Bed Forms

Om kurset

Prof. Southard builds on earlier concepts by examining how different flow conditions, sediment properties, and dimensional analysis combine to produce distinct bed configurations such as ripples, dunes, and plane beds. He uses laboratory data and conceptual models to map out how these features vary with flow velocity, depth, and grain size, highlighting patterns like the transition between flow regimes and the presence of spectral gaps between ripples and dunes. The lecture then expands to oscillatory flows and wave-generated bedforms, explaining how ripple geometry changes from two-dimensional to three-dimensional forms and how complex patterns emerge under natural wave conditions. Southard also introduces the added complexity of combined flows, where currents and waves interact, emphasizing the challenges of predicting resulting structures. The session concludes by linking these physical processes to sedimentary structures preserved in rocks, setting the stage for interpreting past flow environments from geological records.